Glow discharge tube circuit



Oct. 16, 1934. K. swART 1,977,254

GLW DISCHARGE TUBE CIRCUIT Filed March 17, 1953 L 2,7 1 2 I 6 'll-; W Dll x as fifi/5e E l i lf2 n 4 l' 3 E a 7 L1B l1 w f ffm? I -D Il i l' TR1 Y; 11 7 z 1 5 W1 17, 1 "s 2 Ze l l 'E lf2 E 1% *R l2 f f @3256? l l 11T: Z7 l l 60s/wed 2 z l 'z/e E i Z2 l la l I 6 f. El W3- D3 l l asli/beg i i K2 5 Lg; f lNvENToR Z. E Swwlf' ATTORNEY Patented Oct. 16,1934 "UNITED STATES GLOW DISCHARGE TUBE CIRCUIT l Leland K. Swart,Mountain Lakes, N. `J., assigner to American Telephone and VTelegraphCornpany, a corporation of New York i Application March 17, 1933, SerialN0. 661,410

Claims. i (Cl. Z50- 27) This invention relates to electricaltransmission systems. More particularly, the invention relates totransmission systems employing cold cathode gas filled discharge tubeswhich are ca- I 5 pable of operating for both halves of an alternatingcurrent cycle. l

A cold cathode gas 'filled tube of the neon type having two electrodescan be operated when the voltageimpressed across the electrodes equalsor exceeds the breakdown voltage between these electrodes. The voltagerequiredto break down the gap between the electrodes can be reducedbypthe interposition vof a biasing potential such as` a battery inseries with the electrodes. biasing potential actually reduces thevoltage required to cause a discharge between the vactiveelectrodesofthe :tube by an amount which was equal to the magnitude ofthe biasing potential. But the reduced potential required to energizethe tubejhas to-be poled in` a certain direction, i.` e., a direction inseries aiding'relatlon with the biasing, potential, however, beforethere is an actual breaking down pof the gap between. the electrodes ofthe .gas filled tube. It, of course, re-

a discharge betweenthe electrodes of such a tube if impressed' with a`Voltage ,in the opposite direction. y V

`One of the objects of this invention is tovprovide a system including acold cathode gas filled tube which willbe capable of operation whenimpressed with ylow voltages which fiow in either direc-tion.4 otherwords, an object of the invention is to provide an arrangement includinga cold cathode gas lled tube: which will be capablev of operation fromeither half of a cycle of alternating current.

Another of the objects of this invention is to provide a cold cathodegas filled tube having two cathodes and an anode so arranged that thep0- tential required to produce a discharge between either ofthecathodes and the anode will be acertain predetermined value.

Another of the objects of this invention is to include in a transmissionsystem acold cathode gas I'illed tube having two cathodes and an anode,and in addition a source of direct current potential which will be usednot only to bias both of the cathodes with respect to the anode but alsoto produce the current required to energize a translating circuit. i

This invention will be better understood from the detailed descriptionhereinafter following when `read in connection ,with kthe accompany- 545ing drawing, in which Figure 1 represents one em- This quires ayconsiderably higher voltage to producel bodiment of the invention whichincludes one cold` cathode gas iiled'tube; Fig. 2 shows threetranslating circuits each associated with a cold cathode gas filled tubeand a biasing potential common to allof the tubes; and Fig shows threeG0L translating circuits and three corresponding cold cathode gas filledtubes all of which are biased by a common source of directcurrentpotential which also operates a single relay or translating circuit.

Referring to Fig. 1 of the drawing,'the reference character D representsa circuit which may transmit direct currents of either polarity or, moreusually, alternating currents of any frequency. The circuit D isconnected to the primary winding ofv a transformer T. The secondarywinding of the transformer T isconnected to the cathodes K1 and K2 oi acold cathode gas lled tube designated N, the upper terminal of thesecondary winding of the transformer being connected to the cathode K1through a choke coil L and the lower terminal of the secondary windingbeing connected to the cathode K2 through a choke coil L.

The choke coils L andLinay be two equal portions of a single winding orthey may be separate windings having the same number of turns,

, and furthermore, 'it' is preferable that they be wound upon a commoncore of iron. These windings are so poled that if a voltage wereimpressed in series; with them, their inductive reactances would be amaximum.V If, however, the potential impressed lin series Withgeach ofthese windings tends to produce a current now through the coil L in thedirection 2, l and another potential is impressed in series with' thewinding L which tends to produce acurrent ow inthe direction 3, 4, theinductive reactances of the two coils will be equal in magnitudealthough opposite in effect, and therefore the eifective impedance ofthe two coils will be merely that corresponding to their resistance.

The tube N includes, in addition to the cathodes Kr and K2', an anode A..Moreoven the tube is filled with a gaseous medium such as neon, argon,helium crV krypton" or any combination of these rare gases with othergases such, for example, as hydrogen or" mercury vapor. i Theseelectrodes are so spaced within the envelope of the tube N that theVoltage required to break down the gap between the cathode KI and theanode A will be substantially the same as the voltage required to breakdown the gap between the cathode K2 and the anode A. The voltagerequired to break down the gap between the .cathodes K1 and K2 will gen-110 erally be different from that required to break down the gap betweeneither of these cathodes and the anode A, as will be apparent from thedescription hereinafter following.

rThe anodev A is connected to the midpoint of the secondary winding ofthe transformer T through a circuit `which includes a source of directcurrent potential designated B and the winding of a relay designated R,and this circuit may, of course, include any other translating device orcircuit. The source of potential B, which may if desired be an ordinarystorage battery, biases both of the cathodes K1 and K2 equally withrespect to the anode and thereby reduces the additional voltage requiredto break down the'gap between either of these cathodes and the anode.

When a voltage is transmitted from the circuit D through the transformerT and through the choke coils L and L to the cathodes K1 and K2 of thetube N, it will cause ionization of the gas within'thetube N betweenthese cathodes. If this impressed voltage is sufficient to break downthe gap between the cathode K1 and the anode A, current will flow fromthe source B through the winding of the relay R, through the secondarywinding of transformer T, windings L andL, through the ionized gasWithin the tube N from cathodes VK1 and K2,respectively, to anode A.This current will continue to flow so' long as the voltage impressed bysource B between the cath-- ode K1 and the anodeA is greater than thevoltage required to sustain the glow between these electrodes.

yIf the circuit D transmits an alternating current of suiiiciently highpotential, Vthen during one-half 'of the alternating current cycle thegap between the cathode K1 and the anode A will be broken down,.andduring the otherhalf of the cycle the gap between the cathode K2 and theanode Awill be broken down. When either of these gaps is broken down,the impedance'bet'ween the electrodesforming the gap will bereduced froma substantial and almost infinite value to a very low and almostnegligible value. Thegas thus ionized causes current to pass throughreflayR, causing its operation by virtue of 'the presence ofpotential'B. Because of the .presence Aof the coils L and L', thecircuit included between the cathodes K1 and K2 will be protectedagainst such voltages impressed by the circuit D as may tend tocause'damage to these two elements of the tube N itself. However, thecoilsL and L'v are Aso poled that their impedanceto'the flow of currentfrom the source B through the winding 1 of the relay R will be reducedto a limited value,

namely, the actual resistance of-these coils which' may be-consideredconnected in parallel relationship. A Y 1 The source of potential Bwhich has been described hereinabove as one of direct current may, ifdesired, be replaced by -a source of potential which is of thealternating current type. In that event, the voltage transmitted by thesource D, if continuously applied and of a magnitude suffi-i cientlygreat, will tend tomaintaintheJgaps be'- tween either 'of' the cathodesK1 and K2 and the anode A continuously discharged. f Since thecharacteristic ofv alternating current is such that its magnitudebecomes zero twice during each complete cycle, then the gap betweeneither of the cathodes'K1 and K2 and the anode A-will be restored toitsinitial condition at least once' during each cycle. It follows,therefore, that if the source B is one producing an alternating current,it will be unnecessary to include a switch 'or other mechanical devicefor breaking the circuit between the anode A and the midpoint of thesecondary Winding of the transformer T in order to restore the tube toits initial and unoperated condition.

The current emanating from source B passes between the anode A of tube Nand bothcathodes or electrodes K1 and K2 in parallel paths. Thissubstantially increases the current carrying capacity of the tube N.

One of the features of the arrangement shown in Fig. 1 resides in theemployment of the electrodes K1 and K2 both for producing the ionizationof the gas within the tube N and for receiving the currents passedbetween the anode A and these cathodes.

The total voltage of the source B not only biases both cathodes K1 andK2 by its voltage with respect to the anode A so as to reduce thevoltage required to ionize the gas within tube N, but this' same Voltageis employed to energizev the winding of the operating relay R oranyother translating circuitV which is controlled by vthe tube N. f

Fig. 2 shows three translating circuits desig` nated D1, D2 and D3 whichare connected through transformers T1, T2 and Ts to the cathodes K1 andK2 of the cold cathode gas filled tubes N1, N2 and N3, respectively.'Ihe secondary Winding of the transformer T1 is connected to thecathodes K1 and K2 of the corresponding tube N1 through choke coils L1and L1', as shown. The choke coils L2 and^L2 are interposed between thesecondary winding of the transformer T2'and the cathodes K1 and K2 ofthe tube N2, and the coils L3 and L2' are interposed between thesecondary winding of the transformer'T3 andthe cathodes K1 and K2 of thetube N3, as shown. y `i 'I'he anode `A of each ofthe tubes N1, N2 and N2isconnected to the positive terminal of the source B- throughacommoiifswitch designatedS. The negative*v terminal of the sourcelB isconnected to the midpoint! of 'thelsecondary winding of the transformer`T1 'through a switch S71 Yand 'the winding of therelayk R1.V Thenegative terminal ofthe source Bis also connected to the midpoint of thesecondary winding ofthe transformer T2' through a circuit which includesa switch S21-and the 'operating' winding of vthe relay R2.` Furthermore,the negative terminal of the source B is connected to the midpoint ofthesecondary winding of the transformer T3 through a circuit which includesa switch S3 and the operating'winding of the relay R3. n y f y If all ofthe switches S, S1, S2 and Sa are closed, then thesource B 'willbias thecathodes K1 and K2 of each of the tubes N1, N2 and N3 to a common,pred'eterr'ninedv potential with respect to the anode A of each of thesetubes. sufficiently greater than this predetermined value is impressedupon any one of the circuits, such as D1, for-example, it will cause abreakdown'between the gaps established between the cathodes K1 and K2and the anode A in the tube N1 and current will flow continuouslyfromthe source B through the operating'winding of the relay`R1. Currentwillcontinue to flow through the operating winding of the relay R1 eventhough the voltage impressed upon the circuit D1 becomes lower than thevoltage required to cause ionization of the gas within the tube N1.However, if Ithe sourceB is of the alternating current type, any

voltage present yin the circuit D1 which is above' If, then, a potentialdischarged only so long as that voltage remains impressed upon thecircuit D1; Moreover, if the source B1 is-of the direct current type,then the current flowing through the operating winding of the relay R1may be interrupted by opening the switch S1-whenever desired.

If the voltages impressed upon two of the circuits as for example, -D1and D2,or,'in fact, all of' the circuits D1, D2 and D2, are alternatingpotentials exceeding a Vcertain predetermined value, then the gapsWithin all of the tubes associated with these circuits will'be' brokendown and remain broken down vif the switches S, S1, S2 and S3 are allclosed and the source B is of the direct current type.l In -that eventthe source B will continuously supply current to the operating windingsof all of the relays R1, R2 and R3 even though the voltage impressedupon any one or all of the circuits D1, D2 and D3 becomes reduced belowthe predetermined value just mentioned. It will be possible to interruptthe circuit of source B which supplies current to all of the operatingwindings ofrelays R1, R2 and Rs by opening the switch S. However, if itis desired to interrupt the current flowing to just one of theseoperating windings, as for example, that flowing to the operatingwinding of the relay R1,

it will be necessary to open the switch S1 only.

Fig. 3 shows three circuits D1, D2 and D3 which are connected to theprimary windings of transformers T1, T2 and T3, The secondary winding ofthe transformer T1 is connected to the cathodes K1 and K2 of the tube N1through coils L1 and L1', and similarly,` the coils L2 and L2 and thecoils L3 and L3 interconnect the secondary windings of the transformersT2 and T3, respectively, with the cathodes K1 and K2 of the tubes N2 andNa, respectively, as shown.

The positive terminal of the source B is connected to the anode of eachof the tubes N1, N2

and N3 through a switch S which is in common to these circuits. Thenegative terminal of the source B is connected to the midpoints of the Asecondary windings of the transformers T1, T2 v and T3 through theoperating winding of the relay R, which is in common with these threecircuits.

When the voltage impressed upon any one of the circuits D1, D2 and D3 issufficient to break down the gap between either of the cathodes of anyone of the tubes and its associated anode, current will now from thesource B through the operating winding of the relay R. This current willilow continuously and without interruption if the source B is of thedirect current type and if the switch S remains closed. It will bepossible, then, to interrupt the circuit of the relay R merely byopening the switch S. It will be understood,

n however, that the switch S may be dispensed with shown in the drawingthrough the associated choke coils.

It will be further understood that the currents transmitted overcircuitD of Fig. l and over the a circuits D1, D2 and D3 of Figs. 2 and 3 neednot necessarily be alternating currents. If resistances replace therespective transformers T, T1, T2 and T3, for example, then the tubes N,N1, N2 and N3 will become operated even when-direct currents of eitherpolarity are'suppliedbycircuits D, D1, D2 and D3, respectively.

While this invention has been shown and de` scribedin certain particulararrangements merely for the purpose of illustration,l it will beunderstood that the general principles of this invention may be appliedto other and widely varied forms without departing from the spirit ofthe invention and the scope ofthe appended claims.

What is claimed is:

1. The combination of a source of alternating current, a gas filled tubehaving two cathodes and an anode, al transformer the primary winding oiwhich is connected to the source of alternating current, the secondarywinding of said transformer boing connected to the cathodes of said gasfilled tube, a source of potential connected between the anode of thegas filled tube and the midpoint of the secondary winding of thetransformer, and a translating circuit responsive to the flow of currentfrom Said source of potential.

2. The combination of a gas lled tube having two cathodes and an anode,a source of'poten-k tial, a coil connected between the cathodes of saidtube, and a translating circuit, said source of potential beingconnected between the anode of said tube andthe vmidpoint of said coilthrough said translating circuit.

3. The combination of a gas lled tube having two cathodes and an anode,an alternating c'urrent circuit, a translating circuit, a source ofpotential, said alternating current circuit being connected to thecathodes of the tube so that a discharge may occur between one of thecathodes and the anode and the other of the cathodes and the anodeduring alternate half cycles, and means whereby said source of potentialwill equally bias both cathodes with respect to the anode, said sourceof potential also supplying current for operating said translatingcircuit.

4. The combination of an alternating current 120 circuit, a translatingcircuit which is to be operated when the vol-tage in the alternatingcurrent circuit exceeds a predetermined value, a gas filled tube havingtwo cathodes and an anode, means for interconnecting the cathodes ofsaid tube and for coupling said cathodes to the alternating currentcircuit, and a source of potential interconnected between the anode ofsaid tube and said means through the translating circuit.

5. In combination, an alternating current circuit, a transformer theprimary winding of which is connected to the alternating currentcircuit, a gas filled tube having two cathodes and an anode, two chokecoils, one of which interconnects the upper terminal of the secondarywinding of the transformer with one of the cathodes of .the tube and theother of which interconnects the lower terminal of the secondary windingof the transformer with the other cathode of the tube, said coils beingwound series-aiding about a common core of iron, and a source ofpotential interconnected between the anode of the tube and the midpointof the secondary winding of the transformer.

6. The method of operating a translating circuit whenever alternatingcurrent flows through an associated circuit having a voltage greaterthan a predetermined value, with apparatus including a gas filled tubehaving two cathodes and an anode, and a source of potential which biases150 both of the cathodes equally -With respect to the anode, whichconsists in transmitting the currents owing through the associated.circuit to lthe cathodes of they gas lled tube, breaking the gap betweenone of the cathodes and the anode during one half of each alternatingcurrent cycle, alternately breaking the .gapl betweenthe other cathodeand the anode during the succeedinghalf of each alternating currentcycle, and transmitting current from said sourceV of potential throughthe translating circuit as long as either of the beforementioned gaps isbroken down.

7. The combination ofv a first circuit through Which alternating currentflows, a second-circuit to be operated when the voltage through the rstcircuit exceeds a predetermined value, a source of potentialA fortransmitting energy through said second circuit during its operation, agas lled tube having two cathodes and an anode, means'for impressing thecurrentsof the first circuit upon both of the cathodes of the tube,Iand-means responsive to the breaking of the gap between either of thecathodes and the anode for operating the second circuit.

8. The combination of a plurality of circuits each transmittingalternating currents, a plurality of gas lled tubes each correspondingto Yone of the alternating current circuits, each gas filled j tubehaving two cathodes and an anode, a transformer interconnecting eachalternating current circuit with the cathodes of the corresponding gaslled tube,a plurality of relays one corresponding to each alternatingcurrent circuit,

and aA` source of potential, one terminal of nsaid source of potential`being-connected to the anode of each ofsaid tubes, the other terminalof said source of potential being connected tothe midpointV ofthesecondary Winding of each trans- Aformer through the winding of theassociated relay. y

9. The combination of a plurality of alternatingcurrent circuits, aplurality of gas lled tubes each corresponding to one of the alternatingcurrent circuits, each gas lled tube having two cathodes and an anode, a`plurality of transformers each interconnecting the cathodes of one ofthe gas Iilled'tubes with the corresponding alternating current circuit,a source of potential, and a -relay,`one terminal of said source of.potential beingconnected to the anode of each V of said tubes, theother terminal of-said source of potential being connected to themidpoint of the secondary Winding of each of the transformers throughthe winding of said relay.

10. The method of operating a rst circuit when `alternating currenthaving a voltage exceeding a predetermined Value flows through a secondcircuit, with apparatus including a source of potential and a gas lledtube having two discharge gaps, which consists in alternatelydischarging the gaps of said gas lled tube as long as the voltage in thesecond circuit exceeds the predetermined value and continuouslyoperating the first circuit by current from said source of potential aslong as said gaps are being discharged. 2

4LELAND K. SWART.

